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That is interesting, the theory has always been that the GT's benefit more from shrouds than other fans due to their large hub diameters.

Would be nice to see what a range of fan types and speeds does with regards to shrouds and orientation. I have been debating if I should switch my second rad from pull to push when I (eventually) get my GT 2150's, I think I am going to have to do it now.
 

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Discussion Starter · #3 ·
Yeah, the only thing I could think of is the GT's don't produce that typical fan chop and perhaps the space on more conventional fans is actually helping the fan produce more air where on the GT it's just not doing any or much good.

Not sure, but maybe it's not the hub dead spot as much as some sort of air behavior relative to the fan blade.

Push is doing a bit better than pull, but so far the shroud portion also isn't really doing much.
 

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I was wondering the other day about this; given the same air flow (CFM), how does the cooling ability vary with surface area exposed to the flow.

I am thinking that it isn't a simple relationship (aero- and thermo- dynamics is never simple) as with a reduced area the turbulence and flow speed increase which would aid the heat transfer. I think that this increase would, up to a point, compensate for the lower area. If this is right then it may account for the size of the hub not having that much effect on the cooling with the GT. Fancy having a go at testing that?
 

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Discussion Starter · #5 ·
I've seen some odd things when it comes to fans and air. I have tried testing two fans back to back with zero gain, etc using conventional yate loons, so we do know that most fan's are fairly particular about having a smooth undisturbed column of air it's peeling from. The GTs are just a bit different in blade style than most fans which seems to be giving it some different shroud behavior as well.

I do think there is some of that present. Sure there is some dead space behind the hub, but if air flow is constant, then velocity must increase in the areas around the hub. Of coarse flow rate isn't going to be constant if you keep reducing the area, the air restriction will increase and the net flow should decrease.

If I get all caught up I may entertain some sort of "Radiator Masking" experiment using tape or something. I think you will see some decrease, but I'm sure it's not a linear relationship with the surface area since it will make up for it with increase flow in the remaining areas.
 

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So the shrouds are actually hurting performance in push. Stranger and stranger. Perhaps the dead spot is less important than the velocity after all.

I wonder if the pattern will change for different fan types and speeds.
 

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Discussion Starter · #8 ·
Yeah..not what I expected either. Since GTs are pretty popular I will also do a few similar runs ar slow speeds too. I think it is very specific to the fan blade style of the GT. Haven't published yet but I even ran one more push/pull with 25mm shoud on pull and got an 8.60 where push/pull without was an 8.55. The tend continues...at full speed, shrouds don't seem to do any good on GTs.
 

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so shrouds don't even take off 1C
going from pull to push nets you a bigger gain, which i pretty much expected since that's how fans are designed
 

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Discussion Starter · #12 ·
Last round of these I used yate loon slow speeds and they saw very good gains from shrouds at 1350 rpm and also did better in pull over push. I also did ultra kaze 3000 fans running at 2000 rpm and they too saw very good shroud gains but did better in push rather than pull.

I will try the GTs at slower speeds next and see what happens but I am pretty sure the shroud effect thing is very specific to the fan blade type at least and maybe speed as well. Most fans respond well to shrouding.
 

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thumb.gif
Now do a comparison between the EX and RX radiators because I want to see if the EX can perform just as well as the RX rads.
 

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Or you could have a look at Bundy's 360 rad roundup where he actually compares... An EX360 versus a RX360...
Search function!
 

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Discussion Starter · #16 ·
Quote:
Originally Posted by HybridCore View Post

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Now do a comparison between the EX and RX radiators because I want to see if the EX can perform just as well as the RX rads.
Funny you mention that. XSPC already contacted me about sending samples to do some testing. They will be first in the que to get actual full rad testing after this MCR120, and plan to do a pretty large fan RPM sweep from maybe 600 - 4000 RPM over 5 points and two fan types. I do need to order some fans though. I have three GT15s, but only one Delta AFB1212SHE and need two more for doing a triples round.
 

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Discussion Starter · #18 ·
Quote:
Originally Posted by nicodemus View Post

hey martin, i sent you a PM about those XSPC Xinruilian fans. any interest in trying those out? i can send you a few if you like. let me know.
I may try to do a yate loon test if there is time which has a similar 7 blade geometry. The Xinruilian look a lot like Scythe S-Flex or other higher quality 7 blade fan. So while I'd enjoy the tinkering I doubt there would be a significant difference between most other normal 7 blade fans.

I'll see how it goes, I have plenty to keep me busy. I do have a box of about 50 other fans from the old fan testing rounds.
biggrin.gif
 

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Quote:
Originally Posted by Martinm210 View Post

I may try to do a yate loon test if there is time which has a similar 7 blade geometry. The Xinruilian look a lot like Scythe S-Flex or other higher quality 7 blade fan. So while I'd enjoy the tinkering I doubt there would be a significant difference between most other normal 7 blade fans.
I'll see how it goes, I have plenty to keep me busy. I do have a box of about 50 other fans from the old fan testing rounds.
biggrin.gif
haha, ok cool. =) good to know!
 

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Quote:
Originally Posted by Martinm210 View Post

I may try to do a yate loon test if there is time which has a similar 7 blade geometry. The Xinruilian look a lot like Scythe S-Flex or other higher quality 7 blade fan. So while I'd enjoy the tinkering I doubt there would be a significant difference between most other normal 7 blade fans.
I'll see how it goes, I have plenty to keep me busy. I do have a box of about 50 other fans from the old fan testing rounds.
biggrin.gif
i am really interested in the yate loon slows as i have just bought three of them and possibly some more depending on how well they preform with your tests. until then they will be used as case fans.

keep us updated!
 
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